1. Field of the Invention
The present invention relates to a support arrangement determining apparatus, a three-dimensional printing system, and a method of determining a support arrangement.
2. Description of the Related Art
A three-dimensional printing apparatus for forming a desired three-dimensional printed object (hereinafter referred to as a “target object”) by successively stacking layers of a resin material each having a predetermined cross-sectional shape and curing the resin material is conventionally known. This type of three-dimensional printing apparatus forms a target object in the following manner. First, data of a cross-sectional shape of the target object are prepared using, for example, a CAD apparatus. Next, using the data of the cross-sectional shape, a resin layer having a corresponding shape to the cross-sectional shape is formed by curing a photocurable resin. Then, the resin layers corresponding to the cross-sectional shapes are successively stacked to form the target object.
As shown in JP 2003-39564 A, for example, the three-dimensional printing apparatus has a platform having an opening formed therein, a vat placed on the platform, for accommodating a photocurable resin, a holder disposed above the vat and capable of being raised and lowered, and a lighting device disposed below the platform, for emitting light. The light emitted from the lighting device is applied to the photocurable resin in the vat through the opening in the platform. The part of the photocurable resin in the vat that is exposed to the light is cured. By controlling the position of the light to be applied, the position of the resin to be cured can be changed as desired. As a result, a resin layer having a desired cross-sectional shape can be formed. Then, by elevating the holder step by step, resin layers can be formed consecutively toward the bottom. In this way, the desired target object is formed.
When elevating the holder step by step, a resin layer that has been formed needs to support the load of all the resin layers that are to be formed below that resin layer. If there is a resin layer with a small cross-sectional area, it is possible that the resin layer with a small cross-sectional area may not be able to support the load of all the resin layers therebelow. As a consequence, part of the target object may break while forming the target object. In order to prevent such breakage, as illustrated in FIG. 13, a plurality of support objects 130 for supporting part of the load of a target object 170 are attached between a portion of the target object 170 and a holder 113 while forming the object through computing with a dedicated apparatus, such as a CAD apparatus. Then, a whole object including the target object 170 and the support objects 130 integrated with each other is formed. Hereinafter, the support objects may simply be referred to as “supports.”
The supports 130 are attached and arranged, for example, on one of the surfaces of the target object 170 that faces the holder 113. However, depending on the orientation of the target object 170 with respect to the holder 113, the surface of projection of the target object 170 with respect to the holder 113 has a small area, that is, the surface of projection that represents the outer circumferential shape of the target object 170 that is obtained when projecting the target object 170 onto the surface of the holder 113 facing the target object 170 has a small area. As a consequence, the number of the supports 130 attached on the target object 170 becomes insufficient, so that the supports 130 may not be able to sufficiently support the load of the target object 170 during object formation.